Multicolor proof press



SePtl5, 1952 D. D. vANm-:Rcoox Erm. 2,610,581 MuLTIcoLoR PRooF PRESS @OZ/,4 y M Hffyg;

Sept. 16, 1952 Filed March 22,` 1947 n. D; vANDERcooK ET'AL MULTICOLOR PROOF PRESS 14 'sheets-sheet 2 f5 ff Sept. 16, 1952 n. D. vANDERcooK ETAL- MULTICOLOR PROOF PRESS 14 Sheets-Sheet 3 Filed March 22, 1947 5 A K NN @NA F u m L D W H r n w H NS@ n www P. k E MMO L GM S N\ www@ .m w n a @Y W. W A 0f Q ew A N f\..\U.\ WN E MM, v\\\ NY KN %Y\ M m5, SQ w o N\wN a o A Sept 16, 1952 D. D. vANDERcooK vETAL 2,610,581

MULTICOLOR PROOF PRESS Filed March 22, 194'? 14 Sheets-Sheet 4 .57i/E17 22u-'5 Dfw/a Vanns/2600K 50W/mv Q lmasgcooK Sept 16 1952 D. D. vANDERcooK Erm. 2,610,581

MULTICOLOR PROOF PRESS 14 Sheets-Sheet 5 Filed March 22, 1947 ll Tll mi? l.A ifi E E H m h 'SePt- 16, 1952 D. D. vANm-:licoox ETAL 2,610,531

MULTICOLOR PROOF PRESS Filed March 22, 1947 14 Sheets-Sheet 7 rH/Enf" E gig/5 nr/o Vmvosecaak bw/mp 0. Kwak-zanox ,en mao/vo lr. Peu/wo Sept 16, 1952 D. D. vANDERcooK ErAL 2,610,581

MULTICQLOR PROOF PRESS nwo K1A/precoci( [pn/mov 0. Va/voeecoox Parma/vp L. HELL/wv by Q/m if Mm 527275 Sept- 16, 1952 D. D. vANDERcooK Erm. 2,610,581

MULTICOLOR PROOF' PRESS Filed March 22, 1947 14 Sheets-Sheet 9 1 m 5mm t ffm i B BD 0 .m /Ea 1 S 6 v N. 2, u @V10 m y@ mi vM ww n@ D. D. VANDERCOOK ET AL MULTICOLOR PROOF PRESS sept. 16, 1952 Filed March 22, 1947 14 sheets-sheet 11 Sept. 16, 1952 D. D. vANDl-:RcooK Erm.

MULTIcoLoR PRooF PREss Filed March 22, 1947 by @My/MM Sept. 16, 1952 D. D. vANDERcooK ETAL 2,610,531

MuLfrIcoLoR PROOF PRESS Filed March 22, 1947 14 Sheets-Sheet 12 Sept 16, '1952 D. D. VANDERcooK ETAL l 2,610,581

- MULTICOLOR PROOF PRESS Filed March 22, 1947 14 Sheets-Sheet 14 oooonoooyooodhoo Olmi, |'I je lllllllllllllllllllllllllllllllllll llllllllllll Illlllllllll Illllld hren/EPE D4 wp 'Km/amcaak Epu/mea O. Kwvoee cook ,earMoA/p .PeLLAA/p pressions from the same set of forms.

Patented` Sept. 16, 1952 David D. Vanderccok, Evanston, Edward 0. vllandercook, Kenilworth, and Raymond L. Pellavnd,v Chicago, lll., assignors, bymesneassignments, to Vanderccok & Sons, Inc., Chicago, Ill., acor- -poration of Delaware i.Application March 22, 1947, Serial No. 'l36,496

. 1v r This invention relates to a-printingY press; and particularly to a multi-color proof press by which thecolor; composition characteristics of a-set of color printing forms may be determined in advance of their application to high speed production presses but under equivalent conditions of operation as exists in such high speed production presses. j f

The proper preparation of a set of forms for multi-color printing is one of the most expensive and. time-consuming steps of the entire process of producing multi-color printed illustrations. It Ahas been found to be entirely insuiiicient to secure merely a contact impression from the various forms of a multi-color set in advance of the application of such forms to the high speed production presses, inasmuch as the c olor composition of an illustration produced by a given set of multi-color forms on a high speed production press. Will vary substantially Vand unpredictably from that obtained by superposed contact im- It has therefore been recognized that representative proofs canbe obtained in multi-color printing only by taking impressions from the set of multicolor forms under conditions which are substantially equivalent to the printing conditions under which such forms will be usedin `the high speed production press. Heretofore there has not beenr available any satisfactory proof. press which -would'permit multi-color proofs to be obtained from a set of forms under conditions which were truly representative of those encountered in the production presses and which would therefore .provide an accurate proof both as to the coniiguration ofthe particular illustration and the multi-color composition.

Accordingly, it is an yobject of this invention to provide an improved printing press, and particularly an'improved prooi press for obtaining multi-color proofs from a set of multi-color forms.y l l Anotherobject of this invention is to provide an improved multi-color prooi press wherein the speed of operation and the conditions under which the proof is obtained from the set of multicolor'forms are substantially equivalent to that whichv exists in the high speed production presses `in which such forms are to bev utilized, hence vpermitting'a multi-color kprooi" to be obtained which is accurately representative of .the color printing characteristics ofthe particular set of forms V A further object of-.this `invention is to provide, an improved multi-C0101?" .printing press 14. claims. (ci. 1in- 208i '2 y which will accommodate anyl desired number of formsof a multi-color set and selectively produce proofs from such forms consisting'either of a' multiple vimpression of all such forms 'on a single sheet, `a single impression from any seelctedone of such forms, or a multiple impression of any desired combination oi two or morey of Asuch forms.

A particular object of this invention is to provide an improved proofprinting press wherein the forms of a multi-color set of printing forms are disposed in spaced relationship along a longitudinal bed and a carriage is reciprocably movable over such bed vand carries an impression cylinder to which a proof sheet is attached. The inking ofthe individual forms and the speed of the impression cylinder with respect to such forms are accomplished invsuch a manner as to provide printing conditions-equivalent to those of production presses, and mechanism is provided at one end of the bed for loading successive proof sheets upon the impression cylinder and at the otherend of the bed for unloading the printed proof sheet from the impression cylinder.

The specic nature of the invention as well as other objects and advantages thereof will become apparent to thosefskilled in the art from the following detailed description vof the annexed sheetsof drawings which, by way of preferred example only, illustrate one specic embodiment of the invention. 'On the i rawings;"v j

Figurel is a side elevational View of a complete machine embodying this invention showing the v carriage positioned at the loading `end of the bed.

Figure 2 is a view similar to Fig. 1 but showing the carriage positioned at the unloading end of the bed. l

Figure 3 is an'enlarged scale, side elevational view of the loading end portion of the machine of Fig. 1 with the side plates removed.

Figure 4 is an enlarged scale, top elevational view of the central portion of the machineof Fig. 1 showing the carriage traversing such central portion. g

Figure 5 is an enlarged scale top elevational vview of the unloading end of the bed ofthe mashown in Fig. 5'.` r Y )Figure '7 isran'enlargedscale, rear side elevational view of the loading endportion of the: bed

of the machine, showing in particular the chain drive for the reciprocably movable carriage.

Figure 8 is an enlarged scale, side elevational view of one of the inking roller units which is mounted on the reciprocably movable carriage.

Figure 9 isa transverse vertical sectionalview taken alongthe plane IX-IX' of Fig. 8.

Figure 10 is a sectional view taken along a diametral plane through the axis of one of the adjustable circumference pulleys utlizedin the ink roller units.

Figure 11 is an elevational view, partly in section of the pair of gear boxes employedV respectively as drives for moving 'the carriage alongv the bed and for operating the inking rollers.

Figure 12 is a partial side elevational view of Fig. 11 showing the construction oi-one...'o`f lthe brake units.

Figure 13 is an enlarged scale side elevational view of a portion of the carriage, illustrating the adjustable mountingof the vimpression cylinder inthe'` recprocable` carriage.

Figure V14: Ais a vertical Vsectional view Ytaken v'along the 'plane XIV-XIV of Fig'. '13.

Figure' 15 is an 'enlarged scale; 'side elevational View' of a ip'orti'o'n of the reciprocable carriage, "showing the belt and gear 'drive 'for 'the inking roller unit.

.Figure 16 i's a'par'tial topu elevational view `of the mechanism "shown in Fig. 15.

F-gure`17'is a schematic circuit diagramillustrating -one ,possible'electric'al connection arrangement o'f 'the drivin'g'motorsand brakes lfor 'the recpr'ocable carriage 'and inking' me chanism respectively. Y

- .Figure 18 is an enlarged scale 'eievational'view .ofaprtion' of the carriage'rack.

Figure V19 "is a'ppartial side velevational viewof the "forward end. of the bed, showing the buffer mechanism.

Y Figure v20 is aipartial top 'elevational'view'of the lbed, showing' the 'frisk'et chain positioning racks.

.As .shown on the drawings:

-A yery .general description'ofafmlti-Acolor Jproef press embodying this inventionv lwill be first Apresentedlinorder'that the following V'detailed 'description will 4be rendered'more clear withrespect to the functions of .each of the'detailmechanisms Vin Athe machine asa whole.

In general, a machine embodyingthis invention com-prises` a longitudinal; horizontal bed I Vwhich vis 4suitably supported ion. a plurality of 4:spaced -uprights |12.

hereinafter referred to as the loading end and .represented as the .-left hand V.end -of the ima- -chine `vin/Figs. 1 and 2,1a-control box lHl and control panel are provided and feeding platform |61o'verlies panel-Hand box |41and accommodates ,fa-stack of sh'eets to be printed `(not shown) On theitop surface offbe'd v.HJ .there are suitably .mountedra 'plurality ofzform` 'mounting Lblocks 20 -(Fig.. 541) 'permitting the :securing of .anyl desired numberfcf fforlns 125 of .a multi-'color set in longitudinally spaced relationship along the 'bed :|0. L'Beneathithebed l0 afpairrof driving motors 26 `3) fare mounted. and .in.i'addition,` the `gear box 'casing i301 -and brakesfdD. :for Teach zdriving motor.

carriage |00 is fmo'unted onlb'ed l|.`0 .for irecip'roc'able 'movements therealong. Carriage |00 journals an impression cylinder-.|20 l'asiwell Fassa pluralityof'setsfof.inliing roller units |50, 'there -bei'ng nanirking ro1ler-uriit |50 corresponding to each of the form mounting mechanisms on the bed |0.

As the carriage |00 moves along the bed forwardly, i. e., from left to right as viewed in Figs. 1 and 2, the impression cylinder |20 picks up a -sheetofpaper (not shown) `from:the-.loadingr platform |6 and such sheet is wrapped around the periphery of impression cylinder |20. The inking roller units |50 selectively engage the forms 25 to applythe desired color of ink .to such forms 'in advance of the impression cylinder. The impression cylinder is vertically moved in the carriageA |00 Jas the carriage moves along the bed so as toxselectively engage one ormore of the 'forms 25 and thus produce either single color or multi-colorV impressions on the sheet of .jpapencarriedthcreon .At one .end .of #the bed,

At. the extreme forward end of the bed l0, the carriage IIllll comes to rest overlying a plurality of ink applicator roll units 200 (Figs. l and 6) which selectively Vvengagethe inking Aroller `.units |50 to apply a. predetermined vquantity of proper colored vinll: to Ieach of `such zunits. `The printed sheet "is releasedfrom theimpression cylinder |20 at' 'this point, h'encefthe term ,unloading` end of the bed.

YTo preventlthe application of any Vcolor of to any portion of the proof not requiring such color, a plurality vof friske'ts 2150 (Figs. l Yand 4) are provided, there being one "frisket foreach of the forms-of `the multi-color set. The friskets 250 arel supported by a pair of parallel cables 254. The cables 254 are respectively securedat'the forward end-of'thefbed tozupright support members '25E and atl their 'rearwa-rd--endrare `securedlto the bed itself. Intermediate portions of the `cables 254 are trained over sprockets 255 provided on `the top end of uprights i258 on the ncarriage '100. The vcables 255 are also trai-ned over suitable guiding sheaves carried by the carriage HJ!) so'that on the forward movement of `the carriage, lthe friskets are -successively laid over their corre spending forms after the inking roller units have passed thereover, 'but in advance Vof the impression cylinder 120. On theretur-n'movemen-t 'of the carriage |60, the friskets are picked up from the bed |"0 after Ythe impression'cy-linder |20 has passed `t'hereover-but in advance of the inking roller units. Thus the inking roller units v| 50 may contact their respective forms and apply Yink thereto 'during eachd-irection of movementof the carriage |00. As will 'be-seen, the vimpression cylinder |20 is permitted to contact 'selected for-ms `only Vduring the forward stroke -of `the carriage.

'Hence yonly on the forward stroke of the carriage is'the `proof printing accomplished.

Driving mechanism indicated by the .numeral 26 (Fig. 3) ...bolina-motors are respectively connected by Vsuitable :belts 2l vto input pulleys 28 and 29 which are vrespectively journaled on lopposite sides of la gearbox Acasing f30. While the gearibox .casing `30 ;(Fig. 11) fis-a unitarymember, independent-sets 'of speed-reduc'- ing gears are provided within such gear boxfwhich are respectively .driven by :input Vpulleys A28 yand l 29 and .the outputs;.fof lsuch gear. dlrainsxare re- Nspectively repre-sented bythe t shafts 3l'and'2. A sprocket 33 is mounted" on'shaft' 3l and this sprocket supplies driving power for the inking roller units through a chain 34 (Fig. 74). Outconstitutes merely a preferred form and that'any other one of several well known forms of solenoid actuated, vbraking mechanisms could `beadvantageously employed.

Each braking mechanism 49 comprises a pair of substantially semi-circular braking arms 1H which have their one ends pivoted together as indicated at M and are suitably'shapedto snugly surround the brake drums 42, Thefree ends of brake arms il are turned outwardly in y'parallel relationship and are urgedltcgetherby a spring 48 which is mounted on a support rod 5D. j The force exerted by springl 48 is suiiicient tocause the brake arms 4I to exert a' clamping actiongon the drum 42 and hence to rapidly brake the movement ofk the drum 2 and -to substantially lock the drum 42 against rotation. 'Io'releasev the braking action an eccentric 50 is provided to kwhich is suitably connected a pair of links '52 which have their other ends respectively connect- '.ed to the free ends of the brakearms 4l. Hence rotation of eccentric 52 will force such freeends apart and release the braking action, Such rotation of the eccentric 52 may be conveniently produced by a solenoid v56. 'As will be brought out in detail later1 the control circuit for each solenoid 5 5 is interlookedwiththe control circuit for each of the driving motors so that when either vdriving motor is energized, its cooperating braking mechanism 40 is released. d

VAs was heretofore rnentioned,. the sprocket 31 drives the carriage operating chain 38. Sprocket 31 is' disposed at theV loading end ofthe bed YI0 (Fig. 7). and the chain extends substantially the full length of bed il), being trained overa sprocket 39 suitably journaled at the forward end of bed I0. Chain 38 is suitably secured to carriage I las by a buffer arm 62 Awhich has an end. pivotally mounted `to a block provided in depending 'relationship on 'carriage I and vthe other .end ,of Ybuffer arm 52 pivotallyrsecured to one of the links `similar buffer mechanism 69 is provided at the forward end'of bed l0 (Fig. 19) and is engaged by a notch on buffer arm 62. Hence when carriage |00 ismoved to either end of bed I0, its inertia-isabsorbed by hydraulic-mechanisms 68 or rrespectively and brake 4 0 and: it is brought rapidly to a stop Without exerting lundue forcesy fon the bed I0. .i Y v .As was `previously mentionedf the chairi 34' driven by sprocket 33. provides driving .power for the inking-roller'units which are` carried by the carriage Milf-Chain 34 likewise extends the full.

length ofthe 'bed It and'is trained around suitgage'd by a sprocket 12 (Fig. 15)

aci-dosi -a'bie idler sprockets 1n provides artour-th ferlies substantially flush with the top of bed' I0.

In said position the chain 34 is conveniently-'en'- which is jour'- naled 'on the carriage m8. A

From ythe aforedescribed construction, it is ap'- parent that'the sprocket 12 on the carriage |00 may be driven-by chain 34 in two independent manners. When' lthe carriage lll is vstationary fwith respect to the bed i0, then the sprocket 12 Vmay be rotated by energization of the driving 1 motor associated with the sprocket 33.

During the traversing movement of the carriage '|00 along the vbed lll, however, if the chain 34 is locked in position with respect to the bed I8,r as by the braking action of the brake mechanism 4D associated with the driving mechanism lof the sprocket 33, then the sprocket 12 will be rotated by the chain 34 in the same fashion asa gear Vis rotated by rolling along a ilXed rack.

In accordance with this invention, the first condition of rotation of- .sprocket 1 2 is permitted to occur only when the carriage |98 is positioned at the forward end-of` the bed It, `where eachpf the inking rollunits |58 are inengagementwith its corresponding ink applicatorV roll unit 2m). or

when the carriage It!!!v is at the rear or. loading end of the bed. At any other positionof the carriage on'the bed lfthre inking roll driving motor, hereinafter referred toas M1, isrdeenergized andl the brake iii associated withits driving mechanism is applied. 1 *In Fig. 1'7 there is shown in schematic forma suitable circuit for accomplishing such selective energization of the carriage ydriving motor Mo and the inking roll driving motorMr. vIn this circuit diagram the braking mechanism 4d associated with each motor is indicated schematically respectively by the numerals 43o and 53; andthe actuating solenoids for such braking mechanism by the numerals 56e and 561. A pair of contactors 16o and 131 are provided torespectively control the energizationof the carriage driving motor Mc and its associated braking mechanism 40o and the inking roll unit driving motor-M1 and its associated braking mechanism 401. The coils of contactors 16e and v1631 are electrically connected in parallel across a voltage source -lV/r'espectively through the normally closed contacts 18o and the normally open contacts 181 of a limit switch unit 18. Limit switch unit 18 is suitably arranged with respect to carriage IBD so vas V'to be actuated to close contacts 181 and open contacts 13o when the carriage I0@ arrives either ,at the forward end `ofthe bedillt'in. aposition wherein the inking roll units 15S arerespctively engaged with the ink applicator rolls 20`or at the rear end of the bed' lil. The contactorjltr when energized through limit switch unitliiY closes its contacts to simultaneously energize the inking roll unit driving motor M1 and the brake controlling solenoid 561 whichreleases lthe braking mechanism 'til associated therewithi A similar function is performed by contactor 16C when energized, but with respect tothe carriage driving'motor Mc and its associated brake .conitrolling solenoid.

From the 'foregoing descriptionfit ispappar'ent 'that the inkmg m11 unit Meisdeenergizejqfaiig,

its brake applied'thereto 'atall times during'the operation of the .carriage driving motor However. when the carriage It arrives at either the top surface ofthe bed I0. `der |20 issuitably journalledon acoaxial shaft 7 .endeffftheibedel@fthemarriage-drivingmotor. isdeenesizacland its ;b rake -app1iedand the ink.. zing `roll :unit ,motor M :is then energized .and its .brake released.

.It wi11 .0f eoursafhegunderstood by thosesklled in theiart that supplementary controls .are pro- .vided :for thecarriage vdriving motor Mc which will permit such motor Vto be v energizedat the fore Ward end of the bed 4to move the carriage on its ,return Ystr okeand toreverse Lhedirection ,of rotation-of such motor when Ithe carriage has .returned to the rearward or loading end of the bed. Also, it. will be desirable .to .incorporate Controls providing .at :least .two speeds of operai-ionfor @the-carriage driving motor However, all of lauchcontrols -maycomprise any one of'. several 'Conventional forms and hence will vno tbe der 1scribediri further detail herein, except :to point 1 outthatit is convenient to provide a plurality of ;f oo ttcontrcls I8 for carriagemotor Mo along the .length of thebed Ill, .such for. example as .adia- Gflltthe forward, intermediate and rea-r -end portions of Ythe bed as .best showninies'- l end2- Carriage mechanism ""The carriage comprises a frame member of? generally rectangular conguration having hollow', longitudinal extending side wall portions v|0| 4and |02 and transverse wall p ortions |03 and `|04 (Fig. 4). The longitudinal side wall frame portions l|0| and |02 respectively overliey a substantial `portion of the side walls of -bed i0 and @a plurality of support rollers (Figs. 14 and 15) 'aresuitably journaled inthe side frame mem- `lbersvof carriage |00 to support carriage |00 for r free reciprocal movement along bed l0, the rolln ers |05 engaging longitudinal rflanges |05 provided on `opposite sides of thebed l0.

On the top horizontalsurface of bed. |0 there Lisprovided a plurality of form Vsupport blocks '(v- Figg 4) of conventional configuration having a plurality of -dovetail grooves 8 2 therein to receive form clamps S4 to -permit a plurality of forms to vbe positioned in longitudinally spaced relationship along the bed I0 and in identical transverse'relationship with respect to the bed |0. Generally, Afour such form support blocks 20 Awill be provided, inasmuch as most multi-color printing processes employ forms corresponding -respectivelyto the three primary colors and black. 'lt-will, of course, be understood that any desired number of form support blocks 20 may be incorporated in a Vmachine embodying this invention merely by appropriate design of the lengt ovfthe bed |0.

In the rear end of y carriage |00, or the left hand .end thereof as viewed in Figs. 1 and 2, an impression cylinder |20 is mounted, disposed in overlying, transverserelationship with respect to Impression cylin- 22 (Figs. 1 3 andll). The ends of said shaft are respectively iournalled in carriage side walls l, 0 and |02 in eccentric bearings |24. Hence the vertical position of impression cylinder |20 with `respect to the bed I0 maybe controlled by rotationof shaft |.2 2 in its eccentric bearings |24.

Atjthe front face of carriage |00 as viewed in Fig. 1, a radial .arm |25 is suitably secured to shaft |22 which connects such shaft to a positioning. control linkage. The positioning control linkage comprises a link |28 which ,has its ends ,pivotally secured respectively to vradial arm |26 and l.to ra radialr arm `|30 which is co-rotatable .milla pinion 1.3.2. Enionlaz isturn .driven .oy-'.aisectorfeear .I `3.4 whicnis suitably iournaled ,on thside wall |01 of the carriageframe .on a :stud ,shaft |35. .'Ihe pivotal movementof sector gear |34 Ais in turncontrolled by .a cam follower arm |38 whichhas a .cam roller |40 selcured thereto and engaged in a longitudinally ex-'- tending cam track ,|42provideda1ong Y the side .of .mated lo.

Cam track |42 in reality comprises. a pair o parallel,-verticallyspaced groovesor recesses |42a and |.42b,respectively, which extend the entire length of bed 0. At the rear endof the bed l0, .the cam ro l1er,|l4l|A is always engagedinthe .upper groove |4211. Anangular surface |44a (Figs. 1, 2 and 3,.) .communicating ybetween grooves 142e and v |4211 .is vprovided near therear end of the bed to insure the positioning of .cam .roller |40 in upper groove |.4. 2a at suchend. Likewsaan angular :surface |441)v ,is provided at the forward end of bed |0 to insure that the .cam .roller |40 will always be positionedin thelower groove |42b :when the carriage |0 ,is adjacent its Yextremeforward position on the Abed 1 0.

HThe verticalspacing of the grooves |42a-and |4212 is selected to controlthe verticalmovement of impression cylinder |20 with Vrespect tothe vloed |0 between aprinting .and a nonprinting position. Thus when cam roller ,|40 is engaged ,in upper cam groove |42a, the eccentric bearing support `for ,theimpression cylinder 2 0 lowers the impression cylinder ,sufficiently to engage such cylinder with the forms |25 with proper pressure for,. a printing operation. When cam .roller |40 is vengaged in lower cam groove |4211, kthenthe impression Acylinder |20 is raised aboye the b ed 0 toa .non-printing position.

.nt -spaced .intervals along the cam track |42, vcorresponding to the spacing of the forms 2 5 on the .bed L0, switch mechanisms ,|46 are provided to rpermit the cam roller I 40 ,to be selectively Iswitched from one vcam groove to the other as the carriage |00 traverses the 'bed 0 in the forward direction. While any formof switch mechanism might be utilized, 1 preferably .employ a pair ofcooperating switch arms |46a, and |452) respectively for each of theswitch mechanisms |46. llheswitch arm |46a is the primary switch member and is pivoted to the side wall of bed I0 at its forward end, he nce permitting the ,rear ,end thereof to be Vselectively moved about .the pivot from aposition projecting-into the bottom cgroove |4212 to a position projecting Vinto the top groove |42a.

' It will be immediately apparent that switch arm |46a is effective to shift'the cam roller A|40 from one of the cam grooves tothe other only during the forward movement of the carriage on the bed I0. O n the rearward movement of the carriage, the Switch arm |4|a is merely deflected out of the path of the cam roller |40. Hence, since the .cam roller |40 is always positioned Ain the bottom cam groove |42b at the beginning of each rearward strokegit follows that the cam roller |40 always remains in the bottom groove |42b throughout its rearward stroke until it engages the inclined surface |44a near the rear end of the bed l0 whereupon the cam roller |40 -is transferred to upper` groove |4241. Hence, the impression cylinder I2-0 'is maintained in a nonprinting 4position with respect to the y bed l0 throughout itsjrearward strokeandstarts each forward Vstroke a printing position with respect to the-bed I0.

l" The secondary yswitch arm |4617` is pivoted at Vits rea-r end to the side walls of the bed 0 and functions only as a guard rail with respect to the cam roller |40 during the switching movement of such roller. Each arm |46b is pivotally biased by a suitable spring (not shown) to a normal position wherein it projects into upper cam groove |42a. Hence switch arm |46b'can obviously never have any effect upon the cam roller |40 during the rearward movement of the carriage along the bed I0.

It should be noted that the front and rearmost switch unit |46 is disposed immediately adjacent to the inclined surfaces |44a and |441), respectively. With such arrangement, it is only necessary to provide a primary switch arm |46a adjacent inclined surface |44a` and a secondary switch arm |461) adjacent inclined surface |441).

The pivotal position of each of the primary switch arms |46a is controlled by an individual cable |48, all of which extend rearwardly alongv the bed |0, trained over suitable guide pulleys, and are secured to manually operable reels To resiliently bias switch arm I46a to one of its extreme pivotal positions, a spring |49 (Figg 3) is provided which cooperates between each cable |48 and the'bed |0. Hence manual turning of the reels |5| in opposite directions will respectively move the switch arm |46a from one to the other of its extreme pivotal positions. In addition a master lever |475 is provided which will simultaneously move all of the cables |48 to move all the switch arms |'46a from one position to another.

It is therefore apparent that the vertical position of the impression cylinder may be selectively controlled between a y printing and. nonprinting position with respect to any one of the forms 25 by manipulation of the particular switch arm |46a which lies in advance of thatportion of the cam track |42 corresponding to the location of the selected form. Hence, assuming that four forms are mounted on the bed I0, in the traverse of impression cylinder |20 across the bed, the impression cylinder may be selectively engaged with all four forms in succession, or any one of the forms alone, or any combination of less than the entire number of forms. Hence utmost versatility in obtaining either multi-color proofs or individual color proofs is provided.

The impression cylinder |20 rotates only while the carriage |00 is traversing the bed |0. Such portions of the rack |23 while .the portions |236 represent the coarse fit intermediate portions of the rack. f

While not shown in detail, it-viill be understood that the impression cylinder-Imis proa vided with a conventional paper grasping mechanism so that the loading of successive paper sheets on the cylinder will be accomplished automatically each time that the cylinder moves to the rear end of the bed adjacent the loading platform I6. Such mechanism may for example comprise a pair of relatively movable jaws (not shown) extending along the length of the cylinder which are opened by a suitable cam mechanism |01 when the cylinderV |20 arrives at the rear end of the bed I0. Since such mechanism forms no part of this invention, it will be' unnecessary rotation of impression cylinder |20 is produced by a gear r|2| (Figs. 13 Yiand 14) which is coaxially secured to impression cylinder |20. Gear |2| engages a rack |23 which extends along the entire length of the top surface of bed 4`| 0. Therefore the longitudinali-position of any point on the surface of impression cylinder-|20 with respect to anyone of the forms 25 is denitely'determined by the rack |23. To increase the accuracy of the locating actionof rack |23', those portions of the rack which correspondto theposition of the cylinder when engaging thev forms 25 are machined to a high degree of accuracy and provide a close fit` with the teeth on the cooperating cylinder gear |2|; Intermediate portions of the rack |23 are machined to provide greater clearance between the teeth of the rack and the cooperating gear and hence diminish the friction therebetween and the effort required to drive the carriage 00 along the bed l0. This may be conveniently accomplished by lowering the .pitch line of the teeth-of suchsections. This condition is best illustrated inthe `exaggerated showing of Fig. 18, whereinl the portions `|23a represent the ne fit, highly `accurate locating to describe such in further detail except for the pointing out that in Figs. 15 and 16 there is shown the cam operated linkage |01 which is mounted on the carriage |00 .to actuate the paper holding mechanism of the impression cylinder. |20. Linkage |01 comprises a vertical shaft |01a suitably journaled inthe side .wall -of carriage |00 and having a cam follower arm |01b and` roller.|0'|c secured theretoat the lower end and an actuating arm |01d and roller 01j secured to its other end.l Hence an outward movement of cam follower arm |0'lb with respect tor the bed |0 produced by a suitable cam (not shown) will produce an inward movement of cam actuating arm |01d'which may be utilized to releasev the paper clamping mechanism (not shown). Hence paper sheets may be successively loaded on impression cylinder |20 each time that the carriage |0 arrives at its rearwardk position and unloaded therefrom each time Vthat the vcarriage |0 arrives at its forward position. Aswas heretofore pointed out, all printingcontact of the impression cylinder |20 with any selected forms 25 occurs during the forward stroke of the carriage with respect to the bed |0.

hiking roller units As was previously mentioned, the inking roller units are mounted in the carriage |00. There is an inking rollerunit |50 corresponding to each of the form support blocks 20. Hence in the particular machine herein'described, four inking roller units |50 are provided. v

Therinking roller units |50 areimounted in longitudinally spaced relationship on the carriage |00, forwardly of impression cylinder |20. Since each of the four unitsis identical, only l vone'will be described in detail. y

As best shown in Figs. 8 and 9, each inking roller unit comprisesan assemblage of two inking rolls or form rollers |52 which apply ink to one of the forms 25 on the bed I0 and a distributing roller |54 which is mounted in frictional engagement with both of the form rollers. The form rollers |52 are .each journaled in opposed open slot bearing members |56. The bearing members Y| 56 are respectively mounted on the top of posts |58 which are vertically slidable in the frame side walls |0| and |02 of the carriage |00. On one pair of opposed bearing members |56, upstanding support members .|60 are pro-` vided which in turn support. brackets |62 having upwardly lopen slots |64 formed therein.v The;

shaft I 66 of distributing roller |54 isjjournale'dat Veach end in a bearing member |68 having a generally rectangular exterior configuration.A ABear-g ing members |68 are adjustably mounted on bearing supportarms f| 10, respectively.- and the b earing supportarms are in turn pivotally mounted at one end thereof on a transverse rod |12 which is vertically supported in the slots |55. Hence the distributing roller` is gravitationally biased downwardlyy into concurrent vengagement with the two form rollers |52 of each inking roll unit |50. To prevent inadvertent disassembly of the transverse rod |12 from the open top slots IBG aspring pressed retaining detent |1ll is provided in the side walls of the slots IM.

Thevertical position of the form rollers |52l with respect to the bed l0 is controlled asv the carriage moves across the bed to engage eachV set of form rollers |52 only with the form corresponding thereto. As will be seen, each set of form rollers |52 is supplied with a different color of ink and hence it is of utmost importance that the form Vrollers contact only the color form corresponding to the ink color carried by the particular form roller.

The vertical position of the form rollers |52 is of course determined Vby the vertical position of the movable posts |58. A portion of each of the posts |53 is cut awayA and provided with rack teeth'l16. A horizontal shaft |18 is journaled in the carriage side Walls and; supports at each end thereof asector shaped gear |80 whose teeth are meshed Withthe adjacent rack teeth |15. In the center of shaft |18 a sector gear |82 is secured which meshes with rack teeth |85 formed on a cam follower |36 which is `mounted in the corresponding carriage side Walls for lateral movement with respect to said side walls. A roller |88 is .mounted on the bifurcated, inner end of cam follower |86 to engage in a suitable cam track |99) formed on the side wall of the bed lil.

From the foregoing description, it will be apparent Athat the vertical vposition of the form or inking rollers |52 is determined by the lateral position of the cooperating cam followers ISS with respect to the bed The innermost lateral position of cam followers lowers the vertical position ofthe form, rollers |52 with respect to the bed I0 and hence permits the form rollers to engage their corresponding forms 25. Accordingly, the cam tracks |90 controlling the lateral position of camrfollower |86 mayv convenien-tly comprise a groove in the side wallsk of the bedlll. Obviously, a separatecam track |90 is provided for each-inking roll unit |55 `and y accordingly, four grooves-are provided along the sidewall of becll Hl, each groove portion being locatedv adjacent the position of one of the vforni ation, or if for anyreason it is desiredi: that a 12 ing roller |54. YIn the bottom face of cam block va downwardly'opening slot |91 is formed and a cam roller `|951is journaled in such slot.- A pair of cams |99. are then mounted onand secured to. shaft |92 immediately underlying rollers |95. Such cams have a peripheral surface suitably shaped that, actuation of, handle ld from one pivotal position to another will vraise cam block i535 and distributing roller |54 upwardly and loc-k the handle. in such position by the gravitational bias of the weight supported by the cam blocks. On opposite sidesof the earn blocks |95, integral projections |53A are provided which respectively extend beneath integralprojections |9| provided on the. form roller bearing supports |55. If desired, guide pinsY |89 may besecured in depending relationship to the-bearing support projectionsJS-l and. project, downwardly into suitable vertical apertures formedin the projections |93gon theY cam blocks 95'. Therefore, when camgibloclrsA |95 are raised by cams |93 sufficientiyto'engage projections |93, with b earing support projections, il, the bearingsv |55, and-,hencethe form rollersvji52', will be moved upwardly with'respect to the bed lil and locked in such upwardrv position until manuallyV released by return of, handle |94to its original position.

As wasY previously mentioned', a sprocketv l'r is suitably journaled on thecarriage ixadjacent the back sidey thereof and is engaged'by the inking roller driving chain 3d. Sprocket 12 is shaft-coupled to a pinion |83 which in turn drives a gear |81 secure-:l to a belt pulley |19. On the bacl end of Vthe shaft of each of the form rollers |52jan adjustable pulley |11 is Ysecured, As best,Y shown in Fig. l0, adjustable pulley |11 comprises a wellr knownform wherein one conically faced-sheave |11a is axially adjustable/with respect to an opposed conically faced-sheave |1119 to obtain avariation in effective circumference ofthe pulley when engaged by al V- belt. A suitable V' belt |15 is trained around-,thebelt drivingpulley |19 and then successively over each of the adjustable pulleys |11 secured to each of the*y form rollers |52. A pluralityof idler pulleys |13 are j ournaledr on the carriage-in any` suitable manner to assistin the training-of-the'v belt overa suncient extent orfthe peripheryV of each ofV the adjustable pjulleysil'l.'

It is therefore apparent that the described arrangement permits-Vf highlyv accurate adjustments vto be made ofythe Vperiplfieral surface speedsof each setof forml rollers, AsY will be `appreciated -b'ytnose-skiiied in the art; itis-ei;-

tremelydesirable that each, podr.v of Yforni rollers of aninkingroll unit have substantially identical peripheral surface speeds andthatspeed should exactlyy equal the speed` of movement of the carriage relative to theV fcrms,;so asL to eliminate the possibilityof onerosi-,the rollers exerting Ya sliding action whenvinlbontaot with its corresponding form` 275.]Y Whiler it isvansiznpl'e matter to -0btair1fidentical rotational Speeds Of- 2` pair of cooperating form; rollers, it has y, heretofore been, very difficult ,.to.,l obtain identical surface speeds ofthe form rollers and` carriage vdue :to the .practical impossibility of vobtaining form rolljersfy of fidentical diarrieters .or maintaining such diameters identical oncethe form. rollers are nuse; sincethe material from which' the form rollers are.marleiisrelatively deformable.

The distributing .".rolle'rv 54, is'V preferably mounted on its 7 shaft |565:- in a V`well known v manner-soasltohave aniaxial reciprocato'ry move- 

